Serena Williams’ relationship with Alexis Ohanian has been cute on social media for a while now, but the Reddit co-founder’s tweet about the tennis star on Tuesday was particularly poignant.

This week, Williams made it through to the semi-finals of Wimbledon for the 11th time, despite enduring an injury at the French Open and nearly dying last year while giving birth to Alexis Olympia, her daughter with Ohanian.

“I almost died after giving birth to my daughter, Olympia,” Williams wrote in an essay for CNN Opinion in February. “Yet I consider myself fortunate. It began with a pulmonary embolism, which is a condition in which one or more arteries in the lungs becomes blocked by a blood clot. Because of my medical history with this problem, I live in fear of this situation. So, when I fell short of breath, I didn’t wait a second to alert the nurses.”

What Williams went through was so horrific that she could barely do basic activities. On Tuesday, she tweeted about her fans supporting her, and Ohanian responded by calling her journey thus far “remarkable.”

Walking to the mailbox was a painful, exhausting challenge for this woman just 9 months ago.